The present invention relates generally to chewing gum compositions and methods for making same. More specifically, the present invention relates to chewing gum compositions that are more environmentally acceptable than typical compositions.
For hundreds of years, people have enjoyed chewing gum like substances. In the late 1800""s, the predecessor to today""s chewing gum compositions were developed. Today chewing gum is enjoyed daily by millions of people worldwide.
Chewed gum is usually disposed of in the wrapper that initially houses the chewing gum. Likewise, chewed gum can be disposed of in other substrates by wrapping the substrate around the chewing gum.
Although chewed gun can be easily disposed of without creating any problems, chewing gum when improperly disposed of can create environmental issues. In this regard, the improper disposal of chewing gum, e.g., expectorating the chewing gum on a sidewalk, floor, or like area can create a nuisance. Typically, these gum cuds are mainly composed of a water insoluble masticatory part which is represented by the gum base. Due to its formulation, these gum cuds have an adhesive like characteristic. Therefore, the chewed gum cuds can stick to surfaces on to which it is placed. This can create issues if the chewed gum cuds are improperly discarded.
Rapidly biodegradable chewing gums would be a solution to this problem. Conventional chewing gums are formulated from natural and/or synthetic elastomers and resins. Although some natural resins and elastomers such as Chicle, Jelutong, natural rubber, esters of wood rosin, and polyterpene resins may be still used in gum bases, today synthetic polymers such as styrene-butadiene rubber (SBR), butyl rubber, polyisobutylene, and poly(vinyl acetate) are the dominant masticatory substances. Unfortunately, these synthetic polymers are inherently resistant to biodegradation.
There have been at least a couple of attempts at providing biodegradable chewing gum. Published PCT Application No. PCT/US97/11008 discloses lactic acid based copolymers for use as a masticatory substance. The chewing gum base comprises approximately 3 to about 99% by weight poly(lactic acid) copolymers selected from the group consisting of poly(lactic acid-dimer fatty acid-oxazoline) copolymers and poly(lactic acid-diol-urethane) copolymers.
U.S. Pat. No. 5,672,367 sets forth biodegradable chewing gums based on poly(lactic acid-co-caprolactone) elastomers. Although the elastomers may have desirable chewing characteristics, the toxic caprolactone monomer residues may prevent the elastomers from being used as a masticatory substance.
The present invention provides a gum base, and resultant chewing gum, that is environmentally friendly. As used in the application, the term xe2x80x9cenvironmentally friendlyxe2x80x9d refers to chewing gum compositions that: will degrade rapidly; can be easily removed from indoor or outdoor surfaces; can be ingested after chewing; and/or will dissolve in the mouth after a period of chewing.
Pursuant to the present invention, environmentally friendly chewing gum bases are provided that are biodegradable. These chewing gum bases are formulated with poly(D,L-lactide acid) and poly(D,L-lactide acid-co-glycolic acid).
To this end, in an embodiment, the present invention provides a chewing gum comprising: plasticized poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid).
In an embodiment, the plasticized poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid) have a crystallinity of less than about 18%.
In an embodiment, the poly(D,L-lactic acid) has a crystallinity of less than about 10%.
In an embodiment, the poly(D,L-lactic acid) contains at least 5mole percent of at least one component chosen from the group consisting of D-lactic acid and D-lactide segments.
In an embodiment, the poly(D,L-lactic acid) has a molecular weight of from approximately 2000 to about 2,000,000 g/mol.
In an embodiment, the poly(D,L-lactic acid) has a molecular weight of from approximately 10,000 to about 500,000 g/mol.
In an embodiment, the poly(D,L-lactic acid-co-glycolic acid) has a crystallinity of less than about 10%.
In an embodiment, the poly(D,L-lactic acid-co-glycolic acid) includes approximately 20 to about 70 mole percent of at least one component chosen from the group consisting of glycolic acid and glicolide.
In an embodiment, the poly(D,L-lactic acid-co-glycolic acid) has a molecular weight of approximately 10,000 to about 500,000 g/mol.
In an embodiment, the chewing gum includes at least one plasticizer chosen from the group consisting of glycerides (mono-, di-, and tri-), adipates, citrates, poly(ethylene glycol), poly(propylene glycol), and phthalates.
In another embodiment, the present invention provides a gum base. The gum base comprises plasticized poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid).
In an embodiment, the plasticized poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid) have a crystallinity of less than about 18%.
In an embodiment, the poly(D,L-lactic acid) has a crystallinity of less than about 10%.
In an embodiment, the poly(D,L-lactic acid) contains at least 5 mole percent of at least one component chosen from the group consisting of D-lactic acid and D-lactide segments.
In an embodiment, the poly(D,L-lactic acid) has a molecular weight from approximately 2000 to about 2,000,000 g/mol.
In an embodiment, the poly(D,L-lactic acid) has a molecular weight from approximately 10,000 to about 500,000 g/mol.
In an embodiment, the poly(D,L-lactic acid-co-glycolic acid) has a crystallinity of less than about 10%.
In an embodiment, the poly(D,L-lactic acid-co-glycolic acid) includes approximately 20 to about 70 mole percent of at least one component chosen from the group consisting of glycolic acid and glicolide.
In an embodiment, the plasticized poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid) comprises approximately 10 to about 70% by weight of the gum base.
In yet another embodiment of the present invention, a method of manufacturing gum base is provided comprising the step of plasticizing poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid) and adding a resultant product to other gum base components.
In an embodiment of the method, the resultant product comprises approximately 20 to about 70 mole percent of the gum base.
Additionally, the present invention provides a method of manufacturing chewing gum comprising the step of adding a gum base including plasticized poly(D,L-lactic acid) and poly(D,L-lactic acid-co-glycolic acid) to a water soluble portion.
It is an advantage of the present invention to provide an environmentally friendly chewing gum base.
It is a further advantage of the present invention to provide a chewing gum that is biodegradable.
Still further, it is an advantage of the present invention to provide a chewing gum composition made from a biodegradable chewing gum base.
Another advantage of the present invention is to provide a degradable chewing gum containing an environmentally friendly chewing gum base.
Moreover, an advantage of the present invention is to provide a chewing composition that when chewed, if improperly discarded onto a surface, can be easily removed therefrom.